Telegraph switching system



DSC. 14, 1937. L A GARDNER ET AL y2,101,995

TELEGRAPH SWITCHING SYSTEM DeC- 14, 1937- L. `A. GARDNERET AL 2,101,995

TELEGRAPH SWITCHING' SYSTEM Filed March 14, 195e 4 sheets-sheet z ln tl2 IIHII IV I Qui iws I i L. A. GARDNER /NVENTORS- EJ $/NGE-R A TTOPNE YDe 14, 1937- L.. A. GARDNER ET Al. 2,101,995

` TELEGRAPH SWITCHING SYSTEM Filed March 14, 1936 4 Sheets-Sheet 3PRINTER MAGNET CONTROL -1.. A. GARDA/Ef? /NVENTORS F. J. .sm/GER ATTORNE V Dec- 14, 1937 l.. AfGARDNER ET AL l 2,101,995

1 TELEGRAPH SWITCHING SYSTEM i Filed March 14, 1936 4 Sheets-Sheet 4 l NI u mno/NAL fill-|15 43/ OPERATOR F/G. 4 l

\ L. .4. GARDA/El? /NVENTORS ,q J, s/NGER Patented Dec. 14, 1937 UNITEDSTATES vaa'islsrr OFFICE TELEGRAPH swrroHiNG SYSTEMv Application March14,

9 Claims.

This invention relates to telegraph switching systems and particularlyto automatic switching printing telegraph or teletypewritersystemsadapted for stock quotation service.

An object of the invention is to furnish by means of a teletype-writeroperator at the stock .exchange the latest bid and asked prices of anydesired stock immediately upon request from a broker at a remote point.

Heretofore it has been necessary for stockbrokers, when desiring thelatest bid and asked quotations on any stock to call a stock quotationclerk over a private line terminated in a manually operated switchboardlocated at a stock exchange. The operator at this switchboard, uponrequest by a calling broker, connects the calling `broker to Vthe stockquotation clerk who keeps a record of the bid and asked quotations ofall stocks. These quotations are obtained from the stock specialistslocated at each trading post on vthe floor of the exchange.Thisarrangement requires considerable time to obtain the desiredinformation and at times, especially during extraordinarily activeperiods at the exchange, subjects the brokers to considerable annoyancebecause of errors introduced by human agencies involved in verballytransmitting the information. c

According to the present invention the time required to obtain thedesired information is great- V1y reduced and the liability of error dueto human agencies is substantially reduced by the elimination of voicetransmitted quotations between the stock exchange and the stockbrokersoiiices. The present invention provides a system adapted to permit abroker to automatically connect a telegraph sending-receiving printer athis station with a central office in the stock exchange havingreceiving-only printers equipped with projectors and sending printersfor a stock quotation bureau. The operation of a teletypewriter messagekey at the brokers office causes code symbols of a desired stock to beprinted on the tape of an idle printer equipped with a projector system.The symbols as printed on the tape are projected onto a screen in theline of vision of a numberof quotation bureau operators whose equipmentis arranged for association with any one of a group of printerprojectors. A file of the latest bid and asked quotations on aparticular group of stocks is maintained for each operator. T-heoperator which has these quotations on the stockl appearing code,associates a sending printer with the printer projector on which thecode appeared and also with the calling brokers printer sov that she maytransmit the latest bid'and asked quota- 1936, serial No. 68,928

tionof the desired stock to theY calling broker and may valso cause thequotation to appear on the tape and screen of the associated printerprojector.

The invention will be better understood from the following descriptiontaken in conjunction with the drawings in which:

Figure 1 illustrates the equipment in brokers oices for initiating thecall and for transmitting and receiving messages;

Fig. 2 illustrates a plurality of selector switching circuits in thestock exchange central oiiice arranged to Yinterconnect the stationequipment with the central ofce equipment; and

Figs. 3 and 4 illustrate printer projectors and Vsending printers alsoin the stock exchange centraloiiice.

vGeneraal description The circuit arrangement of Fig. 1 is that of anoutlying station at a brokers office referred toas station A. Theequipment shown therein Ycomprises a printing telegraph sending andreceiving unit |0| and calling apparatus. Station Bschematically shown,is similar tok station A and may be located at a different brokersoiiice. The selector switch'ing circuits A and B of Fig. 2 each includeequipment in the central oi'ce responsive to the'ihitiatio'nof 'a callfor connecting the brokers ofce with an idle printer projector Fig. 3a'nd'the sending apparatus ofFig. 4. n

A broker desiring the latest quotation on la particular stock initiatesa call and sends a combination of signals representing code letters toindicate the stock on which a quotation is desired. This is accomplishedby the operation of key |0'| which completes a circuit over a trunkbetween the brokers oillce and thecentral office lat the stock exchangefor. operating the selector shown. in Fig. 2. This selector rotates toiind an idlev printer projector, indicated schematically at 30|, 302,303 and 304. The printer projectors may be of the type disclosed inPatent 2,017,633 -to E. T. Mottram, October l5, 1935. The completion ofa circuit between the brokers office equipment as shown in Fig. l, andthe central oiiice equipment shown in Figs. 2;, 3 and 4, energizesapparatus for starting the motor |04, Fig. 1, andthe motor of an idleprinter projector Fig. v3. The starting of the motor |04 is a signal tothe operator at the brokers oflice to release key |01 for establishingthe sending circuit. The code signals are transmitted by themanipulaiton of the sending contacts |03, and are received by the idle.printer projector selected by the switch.r

vet() .spective second contacts.

shown in Fig. 2. The code letters are immediately displayed on a screen,such as 330, 33|, 332, or 333, depending upon the printer projectorselected. All of the screens are positioned within the vision of all ofthe operators. The apparatus for two operators positions is shown inFig. 4. These operators have available at all times the latestquotations on stocks, each operator having a particular group of stocksto handle. When a stock code appears upon the screen, an operator Yactuates a sending key, such as 400, 42|, 422, or 423 shown in theoperators position Assuming that printer projector 304 has been selectedand that the code appearing on the screen 333 represents a stock handledby operator No. 1, key 423 is operated to associate the apparatusofposition No. 1 with the apparatus of projector 304 and the brokersstation A. A signal light is lighted at each operators position toindicate that the call has been taken. The quotation'is given by themanipulation of the sending contacts of printer 440. When the quotationhas been transmitted and received by the broker, the ap- Detailoperation of the system' Having briey discussed the general operationand structure of the system between the brokers station and the centraloffice in the stock exchange, the manner in which the circuits andswitching contacts are established will now b described in detail.

It may be assumed that the broker at Station A desires to establish aconnection in the central cfce for obtaining a quotation on a particularstock. Call key |01 is operated and establishes a circuit from ground||1 through Vthe contact of relay |4 andthe key contact to the tipconductor |15, thence through the upper winding of relay 208, uppermake-before-break contact of relay 2 Il to positive signal batteryl 2|3. Relay 208 operates and connects ground to the circuit extendingthrough the winding of relay 2|4 to battery. Relay 2|4 vwhich is 'of theslow release type, operates and applies ground at its inner armature andcontact to a circuit extending over the contact and lower outer armatureof 'relay 2|0, resistance 228, armature and contact of stepping magnet2|5 to battery 2|6. Relay 2|1 is normally held operated by the circuitextending from ground through its right-hand winding to battery. Theapplication of ground to the stepping magnet armature reduces thecurrent through the right winding of relay 2|1 below its holding valueand causes the latter relay to release. It will be noted that a secondcircuit was established by the operation of relay V2|4 from groundthrough its right outer armature and contact, left winding of relay 2|1,upper winding of relay 2|| to the wipers on bank 2 of switch S. 'I'hiscircuit is completed as the switch rotates as will be describedhereinafter. The release of relay 2|1 causes the stepping magnet 2|5 tooperate over an obvious circuit from ground, through thecontact of relay2|1, stepping magnet 2|5 to battery. The energization of this magnetmoves the wipers onbanks I, 2 and 3 of the stepping switch S one step totheir re- The energization of the stepping magnet opens the contact atits armature which removes the short circuit from the right-hand windingof relay 2 1 thereby causing relay 2|1.to.reoperate. The ,selectorkcircuit switch is now seeking an idle printer projector. The idle orbusy condition of a printer may be briefly referred to at this time asindicated by battery or ground on the contacts of relays 3|4, 3 5, 3|6and 301 connected to switch bank 2. Battery on the contacts indicatesthat the printer is idle and ground indicates that the printer is busy.Assuming that ground is encountered on the contact of relay 3|4, nocircuit is established for holding relay 2|1 operated through its leftwinding. Relay 2|1 is therefore released as.

soon as the armature of the stepping magnet is restored and the steppingmagnet 2|5 is again energized causing the wipers to move to contact 3.VThis actioncontinues until an idle printer is found.v Let it beassumedthat printers 30|, 302

,break contact of relay 301, conductor.3|1, fth

contact'V of bank 2 and its associated wfiper, through the upper windingof relay 2| |,-the lefthand winding of relay 2|1 to ground at theouterarmature of relay 2|4. At the timeV that this circuit is established,the magnet contact is opened and relay 2|1 released. Relay 2|1 is,therefore, operated through either its left or right winding or both,and held operated through its left Winding after the switch magnet`Contact is restored to normal. VThe switch wipers therefore remainconnected to the fifth contact. The holding circuit for relay 2|1previously traced also operates relay 2| l, thereby removing groundat'the lower make-before-break-contact of relay 2|| and applyingpositive signal battery to conductor 226 extending through the uppercontact of relay 2|0, lower winding of relay 208, conductor ||6, upperwinding of relay H2, closed contact of key |06, transmitting contacts|03, winding of relay ||0, upper contact of relay ||3,

Acontact of relay ||4, to groundl |1. Relays ||0 and. I2 at station Aoperate when this circuit is established. Relay ||0, in operating,closesa circuit extending from oneside of the alternating current powersupply |08, through the winding of relay motor stop contact |05,armature and contact'of relay 0 to the opposite side of the powersupply. Relay operates and, at its left-hand contact and armature,closes a lockingn the position shown when an operating circuitisnotestablished through its upper winding. When a circuit is establishedthrough the upper winding of relay ||2, the magnetism of the 'lowerwinding is overcome and the relay operated in 4the opposite direction.

It will be remembered that relay 2|| operated when printer 304 wasselected. A circuit isthus closed extending yfrom positive signalbattery, through the left-hand winding of polar relay 305, winding ofrelay 404, inner contact of Vre- 1aysH408-4l2, conductor 2|8fth contactand wiper of bank |,Yupper contact of relay 2| upper winding of relay208, tip conductor H5, contact of key` |01 to ground l|1through thelconposes which will be discussed'later.

:tactoi' relay ||4.` Relay 305 is electrically biased -through its rightwinding to V`spacing and when no line current is connected to it, itsarmature lies inthe position shown. When `a circuit is established astraced through its left-'hand winding, the current is sufficient toovercome the biasing current and causes the operation of relay 305 toestablish a circuit for the operation of the printer magnet 32| andrelay 306. Relay 306,`in operating, closes at its right-hand armature'an operating circuit for the motor control relay 322 which starts themotor of printer 304 and establishes a locking circuit for relay 306.Relay 305 through its left outer contact establishes an operatingcircuit for relay 301, and a holding circult for relay 2| I vthrough theswitch contact and Wiper 3, lower winding of relay 2| I to battery. Theoperation of relay -301 connects ground through its contact to the`switch contact of bank 2 which establishes a busy condition to preventother selector switches .from seizing the printer 304.

The foregoing operations take place in response to the operation of thekey |01. The motor control circuits for the printers and 304 areapproximately simultaneously established. The starting of the motor inthe printer IOI is a signal to the brokers station operator to releasekey |01. It will be remembered that relay |I3 was operated by therectified current and thus upon the release of key |01 a circuit isestablished for slow release relay |I4 and a loop circuit is establishedthrough the upper contact of relay II3. The operation of relay II4removes ground from the signaling circuit for disconnect pur- The loopcircuit established by the release of key |01 may be traced frompositive battery at the lower inner contact of relay 2 I I, uppercontact of relay 250, lower winding of relay A208, ring conductor IIS,upper winding of relay II2, closed contact |06, transmitting contacts|03, winding of relay |I0, upper contact of relay |I3, contact of key|01, tip conductor II5, upper winding of relay 208, upper contact ofrelay 2| I, wiper and contact of bank I, conductor 2|8, inner contactsof relays 408 and 4I2, winding of relay 404, left winding of relay 305to positive battery. Positive batteries are now connected to theopposite ends of the loop circuit which extends through the upper andlower winding lof relay 208 which causes the release of latter relay.Relay 2|4 releases which at this time does not affect other apparatussince holding circuits have been established for both relays 2I1 and 2|I. The release of relay 200 establishes an operating circuit for relay2|0 from ground, through the winding of relay 2|0, make Contact of relay2|I to battery.

The operation of relay 2|0 establishes an obvious locking circuit foritself and establishes a loop circuit for sending signals from thestation printer to the central office printer projector. This loopcircuit may be traced from negative signal battery 22|, upper contact ofrelay 2I0, lower winding of relay 208, conductor IIB, upper winding ofrelay II2, contacts |06 and |03, winding of relay ||0, upper contact ofrelay .I I3, resistance IIS, conductor II5, upper winding of relay 208,conductor 225, upper contact of relay 2II, conductor 221, switch bank I,contacts of relays 408 and 4I2, conductor 4I4, winding of relay 404,winding of relay 305 to positive battery. Relay 208Vagain operates andthis operation for obvious reasons has no effect upon the operation ofthe system at this time. 'Relay 404 operates and establishes an obviouscircuit for -lighting lamp 331 to indicate that printer 304 has Abeenselected for a code message.

A code message is transmitted over the loop circuit last established bythe manipulation of the sending contacts |03. Relays ||2 and 305 areresponsive to the message signal impulses transmitted over the loop.Relay 305 operates printer magnet 32| for printing the code signal uponthe tape, which signal is reected upon the projector screen 333. Theoperation of relay I|2 is effective for operating the printer magnet |02so that a home record may be had of the transmitted message. Relay I I0is also responsive to the signal impulses transmitted but has no effecton the power supply to the motor |04 because relay `I Il is locked overits left-hand armature.

There may be as many operators positions as required such as positionsand 2 illustrated in Fig. 4. Each position is equipped with message keysand signal lamps individual to each printer projector and one sendingprinter. Assuming that operator No. l takes the call appearing Yin codeon the screen 333 the message key 423 is operated for associating theVNo. l position printer 440 with the loop circuit. 'Ihe operation of key423 establishes a circuit for operating the position relay 408 from acircuit established through its winding from potentiometer 4A-4B topotentiometer 4C-4D. A second circuit is established from batterythrough the lower contact of key 423, resistance 453, windingofymarginal relay 454 to ground. Relay 454 is used only as safetyapparatus to prevent incorrect operation of printer apparatus if twokeys such as 422 and 423 are accidentallyoperated at the same time. Thecurrent through the one resistance 453 is not suicient to operate themarginal relay but when two keys are operated the current through tworesistances -in parallel such as 453A and 452 causes sufficient currentto flow through the winding of relay 454 to cause its operation. Theoperation of this relay Vplaces a shunt around the printer contacts 442so that a message cannot be sent under thiscondition. A similar safetydevice is shown in the use of the potentiometers such as 4A-4B, 4C-4Dand 4E-4F. If the No.

l` key in operators position No. 1 remains op-y erated after a call hasbeen answered andthe No. 1 key of operators position No.2 is operated,insufficient current will ilow through the winding of relay 4|2 to causeits operation due to the value of the resistances in each potentiometer.It is apparent that under this condition the two potentiometers 4C-4Dand 4E-4F and the windings of two relays are in multiple extending to acommon potentiometer lA-4B through the key contacts. It will be assumedthat only key 423 is actuated and operates relay 408 to establish anobvious circuit through its lower outer contact for lighting lamps 43|and 435 in oper ators positions 1 and 2. If there are more vpositionsthe lamps are lighted in all of4 the vpositions to indicate that thecall appearing on screen 333 is being cared for. The upper outer contactof relay 408 places a shunt around 'the winding oi relay 404 whichcauses its release to extinguish lamp 331. The upper and lower innermakecontacts of relay 408 establish a loop circuit for y.the printer 440,.This circuit may be traced from positive battery throughl the leftwinding Yof relay 305, upper outer contacts of relay 408, upper:innericontacts Vof relay 408, magnet and sending.:

408, conductor 2|8, fth contact and wiper' of selector switch bankconductor 221, upper contact of relay 2| conductor 225, upper Winding ofrelay 208, conductor H5, normal contact of key |01, contact of relay H3,winding of relay ||0, printer contacts |03 and |06, upper winding ofrelay H2, conductor H6, upper contact of'relay 2|0 to negative battery.The stock quotation is given by operator No. 1 by manipulation of thekeys of printer 440and the quotation is received on printer |0| andprinter projector 304. The quotation transmitted appears on screen 333and may be checked by the operator. The complete circuit may thereforenow be released.

Dsconnection 1 l Ihe position operator No. 1 mayrelease th connection bythe transmission of a double shift signal or upper case H whichdisconnects the apparatus in successive steps and shuts down the motorsof printer |0| and printer 304. The operators key 423 is now restored tonormal which releases relay 408 and disconnects the position apparatusfrom the sending loop. The transmissionyof the double shift signal orupper case H opensthe motor stop contacts 323 and |05. Each of thesecontacts is normally held closed substantially in the manner shown inPatent 1,566,295 to E. F. Watson, December 22, 1925 or Patent 1,904,164to S. Morton et al, April 18, 1933 andkmay be opened as shown in thesepatents. The opening of contact 323 releases relay 322 which opens theright-hand motor control contacts and the left-hand holding'circuit forrelay 30B. The latter relay releases and opens the holding circuit forrelay 2|| and the operating circuit for the make-busy relay 301. Thisremoves the make-busy ground from the switch contact which permits theprinter projector 304 toY be again seized by another selector. It willbe remembered that the locking circuit for relay 2|0 is establishedthrough the lower contact of relay 2 i and upon the release of relay 2|l relay 2 l0 releases. The loop extending to the apparatus of Fig. 1 isthus open which causes the apparatus of Fig. 1 to restore to normal.`Attention is directed to the function of relay |4 which is used toprevent the broker at station A from holding the connection between hisoiiice and a printer projector.

The connection could be held by the reoperation of key |01 immediatelyafter the quotation has been received at the station if the start loopcircuit were not held open by the upper contact of relay ||4. To preventthe release of relay ||4 by the reoperation of key |01 a locking circuitis established through the lower contacts of relays ||3 and ||4. Uponthe release of relayr||3 the circuit is opened for relay ||4 but sincethis relay is slow to release, suilicient time is allowed to permit allof the apparatus used in the connection to restore to normal'before theground I1 is again associated with key |01.

In some instances it may be an advantage to have the operator at thebrokers office assume the duty of transmitting the disconnect signalafter the stock quotation has been received. In this case the apparatusof both the station and central oice is restored to normal in the samemanner as described.

What is claimed is:

1. In a signal transmission switching system, the combination of aplurality of sending stations, means at said sending station fortransmitting outgoing signals and recording incomingsignals,

keys of printer 440, lower inner contact of relayA a plurality'of.receiving stations, aV signalprinter at each receiving station, aplurality of transmitting printers common to said receiving stations, adevice individual to each of said sending stations for selecting any oneof said signal printers,

a normally deenergized circuit vextending fromeach of said sendingstations to each of said devices, an electrical contacting deviceat'each sending station operable for energizing one of said circuits andcausingthe associated selecting device to Yselect an idle signal printerat one of said receiving stations, indicating means individual to eachof said signal printers and visible to the operators of all transmittingprinters for informing the operators that a sending station has beenvconnected Vto an idle signal printer and that certain information isrequested by the operator at the sending station whereat the call isinitiated, a plurality of means associated with each of saidtransmitting printers for respectively connecting the transmittingprinter to any one of said cir-` cuits, and means in each of saidtransmitting printers for transmitting the desired information over theoperated circuit to the operator at the calling sending station. Y

2. In a signal transmissionl vswitching system,

Y according to claim 1, wherein the transmitting prising aV plurality ofsending-receiving printer stations and a `central office having aplurality of selector switches, .a plurality of Vreceiving printerprojectors each having a projector screen and means for displaying theprinted matter on the screen and a plurality of sending printers, meansin Yeach sending-receiving printer station for initiating the operationof avselector for selecting an idle receiving printer projector andestablishing a signal transmitting loop, means including the printer insaid stationfor transmitting a code signal to the selected projector,said code signal appearing on the screen of the projector, means in the.central oiiice for associating a sending printer with .the projectorselected and for establishing a sending loop between said sendingprinter and the calling station printer, and means including theassociated sending printer for sending informatory signals to thestation in response to the code signal appearing on the projectorscreen.

4. A two-way printer transmitting system comprising a plurality ofsending-receiving printer stations andra central office having aplurality of selector switches, a plurality of receiving printerprojectors each havingv a projector screen and means for displayingtheprinted matter on the screen4 and a plurality of sending printers, meansin each sending-receiving printer station for initiating the operationof a selector for selecting l an idle receiving printer projectorand'establishing a signal transmitting loop, means operated by saidselection for ,energizing the motor start magnets of the station and4projector printers, means Vincludingfthe printer in said station fortrans- ZAO a sending printer with the projector selectedand forestablishing a sending loop between said sending printer and the callingstation printer, means including the associated sending printer forsending informatory signals to the station in response to the codesignal appearing onthe projector screen, and means for disconnectingsaid sending-receiving loop and arresting the operation of the printermotors.

5. A two-way printer transmitting system comprising a plurality ofsending-receiving printer stations and a central oice having a pluralityof printer projectors, a plurality of selector switches for selectingidle printer projectors, and a plurality of sending printers, means ineach station for initiating the operation of the selector switches andestablishing a signal transmitting loop, means including the stationprinter for transmitting signals to the selected printer projector,means in said projector for displaying the signal printed, means in thecentral office for associating a sending printer with the selectedprinter projector and the station, means including the associatedsending printer for sending informatory signals and a disconnect signalto the connected station, and means responsive to said disconnect signalto prevent the initiation of another call previous to the restoration ofthe station and central oice apparatus involved in the connection.

6. A two-way printer transmitting system comprising a plurality ofsending-receiving printer stations and a central oiice having aplurality of printer projectors, a plurality of selector switches forselecting idle printer projectors, and a plurality of sending printers,means in each station for initiating the operation of the selectorswitches and establishing a signal transmitting loop, means includingthe station printer for transmitting signals to the selected printerprojector, means in said projector for displaying the signal printed,means in the central oice for associating a sending printer with theselected printer projector and the station, a plurality of operatorspositions in said central ofce each having connecting apparatusindividual to each printer projector, and safety means to prevent theconnection of two of said apparatus to the same printer projector.

7. A two-way printer transmitting system comprising a plurality ofsending-receiving printer stations and a central oiiice having aplurality of printer projectors, a plurality of selector switches forselecting idle printer projectors, and a plurality of sending printers,means in each station for initiating the operation of the selectorswitches and establishing a signal transmitting loop, means includingthe station printer for transmitting signals to the selected printerprojector, means in said projector for displaying the signal printed,means in the central oilice for associating a sending printer with theselected printer projector and the station, a plurality of operatorspositions in said central office each having connecting apparatusindividual to each printer projector, and safety means to prevent theconnection of two of said apparatus in one position to different printerprojectors at the same time.

8. A two-way printer transmitting system comprising a plurality ofsending-receiving printer stations and a central oiiice having aplurality of printer projectors, a plurality of selector switches forselecting idle printer projectors, and a plurality of sending printers,means in each station for initiating the operation of the selectorswitches and establishing a signal transmitting loop, means includingthe station printer for transmitting signals to the selected printerprojector, means in said projector for displaying the signals printed,means in the central office for associating the central office sendingprinter with the printer of the station which established the loop, andmeans including the associated sending printer for sending informatorysignals to said station printer as requested according to the signalsdisplayed.

9. A two-way printer transmitting system comprising a plurality ofsending-receiving printer stations and a central oi'lice having aplurality of printer projectors, a plurality yof selector switches forselecting idle printer projectors, and a plurality of sending printers,means in each station for initiating the operation of the selectorswitches and establishing a signal transmitting loop, means includingthe station printer for transmitting signals to the selected printerprojector, means in said projector for displaying the signals printed,means in the central oce for associating a sending printer with theselected printer projector and the printer of the station whichestablished the loop, and means including the associated sending printerfor sending signals to the station printer in response to the signalsdisplayed and to the selected printer projector for displaying theinformatory signals.

LELAND ADAMS GARDNER. FRED JOHN SINGER.

